This invention relates to spectrum analyzer systems and circuits for spectrum analyzer systems and more specifically relates to an improved spectrum analyzer system where the frequency spectrum display is generated on an oscilloscope using just the vertical (Y) axis input of the scope and but a single cable interconnect.
A spectrum analyzer is an apparatus used primarily by engineers for radio frequency electronic design. It comprises a narrow band radio frequency (RF) receiver which is caused to electronically, frequency-scan the input signals, and to produce a calibrated video display of this radio frequency spectrum. Typically, such a display is of frequency as a function of horizontal location and amplitude as a function of vertical rise.
Early equipment had separate RF circuit and display circuit sections, with a multitude of cables between them. Many currently available spectrum analyzers utilize an RF section (subsystem) circuit with an integral CRT display, with both units being incorporated into a single housing.
A few prior spectrum analyzers are two piece; i.e., they have a discrete RF circuit and use a standard oscilloscope as the display component. The RF circuit in these units is a narrow band RF receiver with logarithmic output. This allows for the measurement of input signals having a large dynamic range. The output of the RF receiver is fed to the scope vertical (or Y) input. The receiver frequency is swept from the lowest to the highest desired. A sawtooth wave signal, with its amplitude being essentially a linear function of the receiver frequency, is output to the scope horizontal (or X) input. Controls of frequency and amplitude range are designed within the RF section circuitry. The oscilloscope used must have an external horizontal (X axis) input.